The Mohist School's logical study focuses mainly on the following inference rule: suppose that N and M are coextensive terms, or N a subset of M; it follows that if a verb can appear in front of N, it can also appear in front of M. That is, if 'VM' then 'VN', where V is some extensional verb. Such an approach to logical inference necessitates the study of logical relations among nouns, verbs, and the relations between these two types of words. Evidence is offered here that the Mohists clearly distinguished extensional verbs from intensional verbs, and that this insight enabled them to say, among other things, that VN does not follow from VM, even in cases where N is M or contained in M, as long as the V in question is an intensional verb